The present invention relates to a cover-feeder for isolating the uppermost cover of a flat stack which is continuously advanced, with lateral alignment and as far as a front-edge stop, in an imbricated formation on a transport belt of a feed table.
In cover stations of adhesive binding machines, cover-feeders are known in which the covers to be isolated are stacked in an imbricated manner and while lying flat on a transport belt belonging to a feed table, and are advanced, with lateral alignment, towards a front stop. In the region of its front edge, the uppermost cover is sucked up in a cyclical manner by a series of separating suction devices of a suction head, lifted off the stack which is set at a specific stack height, and transported onwards as a result of a pivoting movement. Drawing-off rollers take over the cover and feed it to a forwarding conveyor.
Since the separating suction devices used in cover-feeders always alight on the uppermost cover at a defined angle which is constructionally determined, it is necessary to adhere to a specific angle of inclination of the cover to be isolated. A marking system for the angle of inclination may be located on the lateral alignment system of the feed table and corresponds to the degree of imbrication of the covers.
In the case of covers which build up more densely in terms of thickness, either uniformly or non-uniformly over the breadth of the cover, shallower feeding of the imbricated formation is necessary so that the cover to be isolated does not arrive under the suction head at too great a height. This would lead to the separating suction devices no longer alighting on the cover at the predetermined angle, a fact which causes malfunctions.
Although the required angle of inclination of the imbricated item can be set by lifting the feed table with the transport belt on the rear side, functionally reliable isolation of covers having a differing thickness over their breadth caused, for example, by data-carrier disks which have been incorporated or by flaps which have been tucked in on one side, is nevertheless not provided.
In addition, there is a danger that, in the case of covers which are not uniformly thick over their breadth, the imbricated formation will increasingly get into a skewed location and will fall apart towards the side which is no longer supported by lateral guides, a fact which requires constant manual intervention.
The object of the invention is to provide a cover-feeder of the generic type which guarantees functionally reliable feeding of covers with flaps which are tucked in on one side or with flaps which are tucked in on both sides with an enclosed data-carrier disk, or covers of that kind which build up in a non-uniformly thick manner over their breadth.
This object is achieved by the fact that the feed table with the transport belt can be positioned obliquely via an adjusting arrangement, transversely to the direction of drawing-off of the covers, in such a way that the elevational line of that face of the covers which is acted upon by the separating suction devices runs parallel to the elevational line of the said separating suction devices. Advantageous further developments emerge from the dependent patent claims.
The invention achieves, for the first time, a way of isolating, in a functionally reliable manner, covers which are fed in a cover-feeder in an imbricated formation and have data-carrier disks, such as CD-Roms, incorporated, or covers having flaps which are tucked in on one side. As a result of the oblique positioning of the feed table with the transport belt, transversely to the direction of drawing-off of the covers, it is possible to counterbalance a skewed location of the imbricated formation and thus adhere to a stable location of the said imbricated formation in the course of forward transport to the suction head. What is particularly important for a functionally reliable procedure, however, is optimum adaptation to the contact height of the separating suction devices, which work at a defined elevational level, and also to the stationary front-edge stops by the raising and lowering of the feed table with the transport belt in the oblique position.